Fast re-route (Fast Re-Route, referred to as FRR) is a network error tolerance policy. The fast re-route may protect a link or a node, and may quickly perform switchover when a fault occurs in the link or the node, so as to reduce a packet loss to the largest extent. IP FRR of unicast is that an IP routing protocol generates a preferred route (a primary route) and a corresponding backup route, so that when a fault occurs in an active path, IP traffic may be switched to a standby path for forwarding. Protocol independent multicast (Protocol Independent Multicast, referred to as PIM) FRR of multicast is that the IP FRR of unicast or a statically configured standby path is used, and the active path and the standby path simultaneously forward multicast traffic, so that when a fault occurs in the active path, the multicast traffic may be switched to the standby path for forwarding.
In a procedure of implementing the present invention, the inventors find that at least the following problem exists in the prior art: because the active path and the standby path simultaneously forward the multicast traffic, network bandwidth is wasted.